In data centers in particular, and in a variety of other circumstances as well, there is a need and desire to provide for the passage of cables, conduits, hoses and other pass-through elements, through openings in floors, walls, ceilings, cabinet panels, etc., while providing for effective sealing of the opening and at the same time accommodating the efficient addition and/or removal and/or rearrangement of the pass-through elements as may be required from time to time. A typical data center, for example, will house a large number of computer servers, arranged in racks, which are connected by cables to other servers, networks, etc. These data centers typically are highly dynamic in the sense that equipment is continually being added and removed, rearranged and reconnected, as networks are expanded, and restructured.
Because of significant heat generated by servers in a data center, and the detrimental effect of such heat on computer performance, it is customary to provide for cooling the servers, usually by supplying conditioned air to the equipment racks. To this end a typical data center is constructed with a raised floor, providing a space for cables, hoses, conduits and other service elements, and also functioning as a plenum for the supply of conditioned air. The elements of the raised floor, typically metal “tiles”, are provided with specially placed outlet openings for the discharge of conditioned air, for example at the front of a rack of servers. The conditioned air, under relatively higher pressure than the ambient air in the data center, is discharged upwardly along the front of the rack and is drawn into the individual servers by internal blowers provided therein.
Also associated with the server racks are one or more floor openings which allow cables and other service elements to be passed through the floor tiles from the under-floor space, for connecting to the servers. These openings, sometimes referred to herein as service openings, are separate from the before mentioned outlet openings for conditioned air. It is important to minimize the escape of conditioned air through these service openings because air released through these openings simply mixes with ambient air in the data center and does not provide efficient or effective cooling of the servers. At the same time, it is desired to provide for the easy and efficient installation, removal and other rearrangement of service elements in these service openings. Accordingly, any sealing means associated with such openings needs to accommodate such rearrangement while at the same time providing for an effective seal against the undesired loss of conditioned air under pressure from the plenum space below the raised floor.
One particularly advantageous form of seal for achieving the objectives stated above is described in the Sempliner et al U.S. Pat. No. 6,632,999, the disclosure of which is incorporated by reference in its entirety. The '999 patent discloses a form of grommet which includes a frame, positioned in or over a service opening and provided with one or more brush-like elements which extend across the opening of the frame and serve to resist any flow of conditioned air from a pressurized enclosure or plenum space into the ambient air on the opposite side of the grommet. The brush-like elements accommodate the presence of pass-through elements, such as cables, conduits, etc. while substantially minimizing air flow through the opening. The arrangement also accommodates and facilitates the installation, removal and rearrangement of the pass-through elements as is necessary in the dynamic environment of a data center.